Question: Subtract. $\dfrac{4}{5} - \dfrac{2}{8} = $
Before we can subtract our fractions, they need to have the same denominator. $\frac{1}{5}$ $\frac{1}{5}$ $\frac{1}{5}$ $\frac{1}{5}$ $\frac{1}{5}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\dfrac{4}{5}$ $\dfrac{2}{8}$ $\dfrac{4}{5}-\dfrac{2}{8}$ Let's look at the multiples of each denominator and see which multiples they have in common. Denominator Multiples ${5}$ $5, {10}, 15, 20, 25, 30, 35, \underline{40}$ $8}$ $8, 16, 24, 32, \underline{40}$ The least common denominator is ${40}$. Let's use multiplication to make each fraction have a denominator of $40$. ${\dfrac{4}{5}}=\dfrac{{4} \times {8}}{{5} \times {8}} = {\dfrac{32}{40}}$ $\dfrac{2}{8}}=\dfrac{2} \times 5}{8} \times 5} = {\dfrac10}40}}$ Now, we can subtract ${\dfrac{32}{40}} - \dfrac{10}{40}}$. $\dfrac{32}{40}$ $\dfrac{10}{40}$ $\dfrac{32}{40} - \dfrac{10}{40}$ $=\dfrac{{32}-10}}{40}$ $= \dfrac{22}{40}$ ${\dfrac{4}{5}} - \dfrac{2}{8}} = \dfrac{22}{40}$ We can also write $\dfrac{22}{40}$ as $\dfrac{11}{20}$.